SEOUL — Nearly 90 South Korean families crossed the heavily fortified border into North Korea on Monday to be reunited with relatives they had not seen since being separated in the chaos of war nearly seven decades earlier.

Brothers, sisters, cousins, nephews and nieces cried and embraced each other in the first family reunions to take place in three years, a symbol of thawing ties across the Korean Peninsula.

Some relatives could not even recognize each other, but that was not a problem for 88-year-old Kim Byung-oh and his 81-year-old North Korean sister Kim Soon Ok, who were separated while still at school.

“I haven’t slept a wink since being selected for this family reunion,” Kim Byung-oh said as he met his sister, according to brief pool reports supplied by South Korean reporters.

The reunion program began in 1985, stalled, then got underway again at the turn of the millennium. In all, more than 17,000 South Korean families have taken part in 20 reunions since then. A few thousand others have participated in a brief program of video linkups.

But North Korea’s suspicion of any outside influence means that many tens of thousands more have been denied the chance to meet: More than 130,000 South Koreans have registered as members of divided families since the program began, but more than half of them died before they were able to meet their relatives again. Of those still on the waiting list, more than 12,000 are over 90 years old.

For many participants, these reunions represent the first news they have had of their relatives in nearly seven decades.

“It is a shame for both governments in the South and the North that many of the families have passed away without knowing whether their lost relatives were alive,” South Korean President Moon Jae-in told a meeting with presidential secretaries Monday.

Moon is himself a member of a divided family: His parents fled on a ship from the North Korean port of Hungnam in December 1950, and he accompanied his mother to meet her younger sister during an earlier family reunion in 2004.

“Expanding and accelerating family reunions is a top priority among humanitarian projects to be carried out by the two Koreas,” he said. He also appealed for families to be allowed to exchange letters.

The South Korean families, 89 applicants usually with two or three relatives accompanying them, were bused across the border on Monday morning to the North Korean resort of Mount Kumgang.

Many were war refugees who fled south during the war, leaving relatives behind. Some crossed in wheelchairs pushed by relatives and Red Cross volunteers. The oldest was a 101-year-old man.

As the meetings got underway Monday, North Korean sisters Kim Gyong Sil and Kim Gyong Yong waited nervously for their mother to arrive. The sisters, 72 and 71, respectively, were dressed in violet hanboks, the Korean traditional dress, and as their mother approached, they stood up, bowed and burst into tears.

They cried loudly for several minutes, before finally settling into conversation. Their mother, Han Shin-ja, 99, did not let go of their hands the entire time they were talking.

But the reunions are often also tinged with frustration, with many North Koreans determined to publicly demonstrate their allegiance to the regime, out of genuine loyalty or just fear. In past reunions, some North Koreans have even sung propaganda songs, something that can cast an understandable chill over the gatherings.

Indeed, South Korean Cha Je-keun, 84, soon got into an argument with his 50-year-old nephew, Cha Sung Il, of North Korea. Agreeing that the two nations should be reunified, the younger man exclaimed: “American bastards should be expelled.”

Cha Je-keun tried to explain that the Korean War took place because North Korean leader Kim Il Sung invaded on June 25, 1950.

“Yeah, that was good,” Cha Je-keun answered with a smile, ending the quarrel.

After an initial two-hour meeting, the families sat down for dinner together, looking much closer and at ease with each other. The banquet featured a range of North Korean delicacies, as well as state-brewed Taedonggang beer and strong spirits. The families were seen clinking glasses and putting food on each other's plates.

In the last round of reunions in 2015, Kim Hyun-sook met her North Korean daughter and granddaughter but felt they could not speak freely in front of her.

“What they told me was shaped by the communist regime,” the 90-year-old said. But she added that it was still an emotional, if bittersweet, moment.

“It was hard to say goodbye. In fact, meeting them for that little moment made me miss them more ardently than before,” she said in an interview. “I really wish I could see them once more while I am alive, but I can’t go to a reunion event again because I have already been once.”

A second round of reunions involving an additional 83 families will take place from Friday to Sunday. While South Korea chooses participants through a computerized lottery, experts say North Korea selects candidates based on their perceived loyalty to the regime.